Drafting instrument



-Dec., 5, 19441-, W W, HILL 2,364,529

Y DRAFTING INSTRUMENT Filed March 9, 1945 e" 'IIa/ggg] l2O l 21 'ff/Al. l@

Patented Dec. 5, 1944 UNITED STATES PATENT OFFICE DRAFTING INSTRUMENT Walter W. Hill, Washington, D. C.

Application March 9, 1943, Serial No. 478,549

4 Claims.

This invention relates to drafting instruments and more particularly to an instrument for use on a drafting board to permit the drawing of angles, circles. polygonal openings and other marks in order to speed up the drawing of the parts relating to the particular element. l

Another object of thisv invention is to provide an instrument of this kind which may be made out of plastic orother substantially transparent material, and which may be used with either face contacting with the drafting paper or board.

Another object of this invention is to provide an instrument of this kind including an improvide handle which is reversible and is adapted to project from the upper side of the instrument sc as to facilitate lifting the instrument from the drafting board.

A further object of this invention is to provide in an instrument of this kind a series of protractor openings to permit spotting angles on the drawing and also permit the marking of bolt heads or screw heads without the use of a small compass.

A further object of this invention is to provide an implement of this kind which can be used during either the pencilling or the inking of the drawing.

With the above and such other objects in view, as may hereinafter more fully appear, the invention consists of the novel construction, combination and arrangement of parts as willbe more specifically referred to and illustrated in the accompanying drawing wherein are shown embodiments of the invention, but it is to be understood that changes, variations and modiii- 1 cations may ibe resorted to which fall within the scope of the invention as claimed.

In the drawing:

Figure 1 is a plan view of a drafting instrument or tool constructed according to an embodiment of this invention;

Figure 2 is a detail side elevation of the device;

Figure 3 is a fragmentary sectional View taken on the line 3-3 of Figure 1;

Figure 4 is a fragmentary sectional view taken on the line 4--4 of Figure l; and y Figure 5 is a fragmentary sectional view taken on the line 5-5 of Figure 1.

Referring to the drawing the numeral I0 designates generally a plate of generally rectangular configuration which may be constructed out of suitable plastic material which is preferably transparent and of fairly rigid construction. The plate I0 hasI one edge thereof, designated by reference character II, cut on an angle as at I2. and as at I3.

The angled portions I2 and I3 converge toward the center of the plate Ill, and the angles of the cutout portions I2 and I3 are alike, lbeing preferably a fifteen degree angle with respect to I3, the V-shaped portion I4 projecting outwardly i and the angle formed by the sides I5 of the V- shalped portion I4 is preferably an angle of eighty-two degrees l(82") which is in conformity with the angles of the heads of screws or the like.

The edges I6 and I1 of the plate Il) extend at right angles from the edge II and are disposed at right angles to the edge I8 which is opposite from the edge II, and is parallel with the latter edge. The edges I6, I1 and I8 may be provided with graduations I9 extending throughout the length thereof, which graduations may be in inches or fractions thereof. The marginal edge of the plate vII] is 'bevelled as at 20 thereby providing a relatively thin portion 2I which may be placed in Contact with the upper side of thedrawing during the time that the drawing is being pencilled, and when the drawing is being inked the side 22 of the plate Il] may be placed lowermost with the side 23 uppermost so as to place the marginal edges of the plate I0 above the drawing paper so that the pencilled lines may be inked without blurring the lines as would be the case if the edges. of the plate I0 were squared 01T from face to face.

The plate I0 is formed with a plurality of circular openings 24 which are of varying diameter, the diameter increasing from the small opening 24a to the larger opening 24D. The plate I8 is also formed with a series of progressively increasingpolygonal openings 25 which progressively increase in size from the small polygonal opening 25a to the larger opening 25D. The polygonal openings 25 are provided for the purpose of drawing the heads of hexagonal bolts or the like. The plate I0, about the marginal edges of the polyg onal openings 25a, is bevelled, as at 26, after the same manner as the bevel 20. The bevel 26 extends from the side 22 of the plate Ill and provides a means whereby the polygonal openings will permit the use of a pencil to mark the openings on the drawing when the instrument is disposed With the face 23 lowermost and may be used for inking the drawing when the face 22 is lowermost.

The plate I0 is formed with a pair of elongated slots 21 and 28, the slot 21 being disposed on an angle of 45 degrees to the side I I, and the slot 28 being disposed on an angle of 60 degrees to the side II. The marginal edges of the two slots 21 and 28 are also bevelled to permit the use of a ruling pen within the slots 21 and 28. The plate Ill is also formed with a second pair of slots 29 and 30. The slot 29 is disposed on an angle of 45 degrees to the side II and is at right angles to the length of the slot 21. The slot 30 is formed on an angle of 60 degrees to the side I I and is disposed in a reverse position from the slot 21.

One side 3| of the slot 29 is straight and is bevelled, as at 32, and is also provided with graduations 33 indicating inches or fractions thereof. The opposite marginal edge of they slot 29 is formed with cutouts simulating the tops of hexagonal nuts or bolt heads, in side elevation. This marginal edge is cut out on a convex curve, as at 34, on a relatively long arc and is also cut out on a pair of convex curves 35 and 36 extending from the opposite ends of the curve 34. The curves 34, 35 and 36 represent the top of the bolt head or nut, and lines or markings 31 extend from the curves 34, 35 and 36 to a base line 38. At the corners of the simulated bolt heads there are two holes 39 through which the point of a pencil may be extended to indicate the thickness of a bolt head or nut having-the particular configuration shown by the desired size of bolt head or nut. There are a series of these bolt heads or nuts shown on the plate Hl, which are of increasing size from the bolt head or nut 40, to the bolt head or nut 4I The various bolt heads or nuts are spaced apart a slight distance and the adjacent edge of the slot 29 between the bolt heads or nuts is straight, as indicated at 42.

The slot 30 is similar in the configuration of the marginal edges thereof to the slot 29 being formed with one edge 43 straight, and the other 44 thereof cut out on convex curves to simulate the tops of bolt heads or nuts.

The plate I0 is also formed with a V-shaped cutout 45 which extends from the lower circular opening 2417. The V-shaped opening 45 is formed with a flat bottom 46, and is provided to form certain threads of conventional construction. One side 41 of the V-shaped opening 45 extends at a tangent to the circular" opening 24h.

The plate I0 is also provided with a protractor means, being formed with a series of circularly arranged graduations 41 which intersect tapered holes 48 formed through the plate I0. There may be as many graduations and openings 48 as may be desired and they are designated by numerals 49. The center of the semi-circle formed by the openings 48 is indicated at 50, and preferablya pair of crossed hair lines 5I are provided to determine the exact center of the protractor. The graduations 41 extend from the openings 48 to the adjacent marginal edges of the plate I0, as shown in Figure 1.

For the purpose of drawing screw threads through the long axisvof a screw threaded body, I provide a serrated opening 59. This opening may be provided in any convenient part of the plate I0 and obviously the openings may vary in size and number.

In order to provide a means whereby the plate is formed with .a polygonal recess 58. The plate I0 on the side 23 thereof, is formed with a polygonal recess 59.

The shaft 53 is formed at its outer end with a hexagonal head 60 which, in one position of the handle, is adapted to seat in the recess or socket 58. The shaft 54 at its outer end is provided with a hexagonal or polygonal head 6| which, in another position of the plate l0, is adapted to seat in the recess or socket 59. As shown in Figure 5, when the head 6I is seated in the socket or recess 59 the lower side thereof will be flush with the side 23 of the plate I0. When the head 60 is in the recess 58 the outer side of the head 60 will be flush with the side 22. The two shafts 53 and 54, when coupled together, are longer than the thickness of the plate I0 so that a selected one of the heads will, at all times, project above the upper side of the plate I0.

The slidable mounting of the handle 52 provides means whereby the plate may be readily reversed in its position and in either position of the plate I0 there will be a projecting handle portion above the upper side thereof.

I claim:

1. A drafting instrument comprising a flat plate provided with graduations about certain edges thereof, said plate having opposed sockets in opposite faces thereof and an opening communicating said sockets, a handle for said plate having a shank disposed at right angles to said plate and loosely engaging through said opening and provided with a head at each end of said shank selectively engageable in said sockets.

2. A drafting instrument comprising ailat plate provided with graduations about certain edges thereof, said plate having opposed polygonal sockets in opposite faces thereof and an opening communicating said sockets, a reversible handle for said plate, said handle including a shank loosely engaging through said opening and having a length greater than the thickness of said plate, and a polygonal head at each end of said shank, a selected head being engageable in a lower socketI when one side of said plate is disposed on a plane surface with the other head disposed above the other side of said plate and adapted to hold said handle against rotation relative to said plate.

3. A drafting instrument comprising a substantially transparent plate provided with graduations about certain edges thereof, said plate having oppositely facing sockets in opposite faces thereof and an opening communicating said sockets, and a handle for said plate slidable in said opening, said handle including a shank disposed at right angles to the faces of said plate and formed of aligned shank portions, one shank portion having a threaded socket and the other shank portion being formed with a reduced threaded stud engaging in said threaded socket, and a head at each end of said shank selectively engageable in a socket, each head having a thickness substantially equal to the depth of a correlated socket whereby the lowermost head will be entirely contained within its socket.

4. A drafting instrument comprising a plate formed with aligned recesses in the opposite sides thereof and an opening communicating with said recesses, a handle slidable through said opening and a head at each end of said handle engageable in a selected one of said recesses, said recesses and said heads being so formed as to thereby hold said handle against rotation relative to said plate.

WALTER W. HILL. 

